1. PARTNERS: UNIVERSITY OF GDANSK GDANSK UNIVERSITY OF TECHNOLOGY NICOLAUS COPERNICUS UNIVERSITY TORUN MEDICAL UNIVERSITY OF GDANSK OBJACTIVES: An impact of the Vistula River catchment on the biological state of the of Gulf of Gdańsk due to three economic scenarios These scenarios are: Policy targets - high scenario (5-6% growth in GDP in 2004-2020, this allows to realize the Program of Municipal Wastewater Treatment in aglomerations between 2 000 until 2010) The impact of the Vistula river on the coastal water of the Gulf of Gdansk Scenarios analyses by ecohydrodynamic model EUROCAT (Contr. No. EVK1-CT-2000-00044) JAN JĘDRASIK, MAREK KOWALEWSKI, BOGDAN OŁDAKOWSKI, JACEK NOWACKI, AGATA KOT-WĄSIK, JACEK NAMIEŚNIK Policy targets – low scenario (2-4% growth in GDP in 2004-2020, the Program of Municipal Wastewater Treatment will be realized by the end of 2015.) Deep Green scenario (the Program of Municipal Wastewater Treatments until 2010; detergents without phosphates is reduced by 90 %, use of mineral fertilizers is decreasing). The projections for above scenarios determine the discharge of total N and P from the Vistula River into the Gulf of Gdańsk. In order to meet the objective of the study the integrated 3D hydrodynamic and ecological model ProDeMo has been applied. The ProDeMo model describes basic biological and chemical processes taking place in the sea environment. It includes 18 state variables, which can be divided into several functional groups: phytoplankton, zooplankton, nutrients (in water and sediment phases), detritus, dissolved oxygen. Baltic Sea grid step: 5 NM Phytoplankton includes autotrophic organisms divided into five groups: spring diatoms, dinoflagellate, green algae, blue-green algae and autumn diatoms. Zooplankton is restricted to a group of organisms feeding on phytoplankton. Detritus includes all dead matter, which undergo mineralization. Inorganic forms of nutrients include: N-NO 3, N-NH 4, P-PO 4, Si-SiO 4. The ecohydrodynamic model of the Baltic Sea Eurocean 2004, Galway Ireland, slide 1

2. The impact of the Vistula river on the coastal water of the Gulf of Gdansk Scenarios analyses by ecohydrodynamic model EUROCAT (Contr. No. EVK1-CT-2000-00044) JAN JĘDRASIK, MAREK KOWALEWSKI, BOGDAN OŁDAKOWSKI, JACEK NOWACKI, AGATA KOT-WĄSIK, JACEK NAMIEŚNIK Due to the fact that in the analyzed scenarios the reduction of phosphorus loads is much higher (more than 40 %) than nitrogen loads (less than 10 %) the phosphorus becomes a limiting nutrient in the Gulf of Gdańsk. Further reduction of phosphorus load should lead to the reduction of biological productivity in the Gulf of Gdańsk.Due to the fact that in the analyzed scenarios the reduction of phosphorus loads is much higher (more than 40 %) than nitrogen loads (less than 10 %) the phosphorus becomes a limiting nutrient in the Gulf of Gdańsk. Further reduction of phosphorus load should lead to the reduction of biological productivity in the Gulf of Gdańsk. Potential exploitation by end users The developed 3D modelling method as well as the obtained results are of special interest for decision makers responsible for coastal zone management at the national and the European level. Furthermore, the policy targeting on the reduction of nutrients should not limit to the single gulfs but has to cover the whole catchment of Baltic Sea. Eurocean 2004, Galway Ireland, slide 2 Results: Reductions of biological productivity for all scenarios are not very significant comparing to the reductions of phosphorus loads( from 40.9 % for the Policy target low scenario to 45.5 % for Deep green scenario).Reductions of biological productivity for all scenarios are not very significant comparing to the reductions of phosphorus loads( from 40.9 % for the Policy target low scenario to 45.5 % for Deep green scenario). The lowest biological productivity has been obtained for Deep green scenario: the primary production is 7.5 % less than in the reference year 2002.The lowest biological productivity has been obtained for Deep green scenario: the primary production is 7.5 % less than in the reference year 2002. The reduction in biological productivity for Policy targets low and high scenarios are 7.0 % and % 7.1 respectively less than in the reference year 2002.The reduction in biological productivity for Policy targets low and high scenarios are 7.0 % and % 7.1 respectively less than in the reference year 2002. The costal waters are the most biologically productive areas of the Gulf of Gdańsk including the recreational area along the beaches in Gdańsk and along the Vistula Lagoon ( the reduction of primary production rate in these areas is rather low).The costal waters are the most biologically productive areas of the Gulf of Gdańsk including the recreational area along the beaches in Gdańsk and along the Vistula Lagoon ( the reduction of primary production rate in these areas is rather low).